Monday, April 27, 2009

Optical path length of my diagonals

Since the BF10 is measured to be around 7.3cm, so my previous approximation is too rough really.

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Ranger Transformation Project on the lauching pad:

1. Measured once again for the focus position:

- With 2" mirror diagonal and 2" Pentax SMC XL 40mm, I will need to pull the diagonal at 0.5cm outside to reach focus, which is good enough... given the adapter might have some length (sure it will), the focus travel is about right.

- With the 2" mirror diagonal and my 1.25" 20mm Widescan Type III, it's around "parfocal" with the Pentax 40mm when used with the 2"->1.25" adapter

- With the 2" mirror diagonal, the 13mm Nagler requires more out travel, so maybe I will need to use my filter thread extension tube on the Nagler, so it's also use-able

- 5x Powermate is parfocal, so there's no problem with that Nagler!

For solar imaging, since the BF10 has around 4cm optical path less than the 2" mirror diagonal, my 1.5 inch 2" extension tube from the JMI NGF-S will work perfectly to make that up! Everything ready!